Inflammation after Ischemic Stroke: The Role of Leukocytes and Glial Cells

The immune response after stroke is known to play a major role in ischemic brain pathobiology. The inflammatory signals released by immune mediators activated by brain injury sets off a complex series of biochemical and molecular events which have been increasingly recognized as a key contributor to neuronal cell death. The primary immune mediators involved are glial cells and infiltrating leukocytes, including neutrophils, monocytes and lymphocyte. After ischemic stroke, activation of glial cells and subsequent release of pro- and anti-inflammatory signals are important for modulating both neuronal cell damage and wound healing. Infiltrated leukocytes release inflammatory mediators into the site of the lesion, thereby exacerbating brain injury. This review describes how the roles of glial cells and circulating leukocytes are a double-edged sword for neuroinflammation by focusing on their detrimental and protective effects in ischemic stroke. Here, we will focus on underlying characterize of glial cells and leukocytes under inflammation after ischemic stroke.

Erratum: In vitro and in vivo anti-Helicobacter pylori activities of FEMY-R7 composed of fucoidan and evening primrose extract / 한국실험동물학회지

As the request of the authors, Acknowledgments section has been changed.

In vitro and in vivo anti-Helicobacter pylori activities of FEMY-R7 composed of fucoidan and evening primrose extract / 한국실험동물학회지

Effects of FEMY-R7, composed of fucoidan and evening primrose extract, on the bacterial growth and intragastric infection of Helicobacter pylori as well as gastric secretion were investigated in comparison with a proton-pump inhibitor pantoprazole. For in vitro anti-bacterial activity test, H. pylori (1x10(8) CFU/mL) was incubated with a serially-diluted FEMY-R7 for 3 days. As a result, FEMY-R7 fully inhibited the bacterial growth at 100 microg/mL, which was determined to be a minimal inhibitory concentration. In addition, 6-hour incubation with H. pylori, FEMY-R7 inhibited urease activity in a concentration-dependent manner, showing a median inhibitory concentration of 1,500 microg/mL. In vivo elimination study, male C57BL/6 mice were infected with the bacteria by intragastric inoculation (5x10(9) CFU/mouse) 3 times at 2-day intervals, and simultaneously, orally treated twice a day with 10, 30 or 100 mg/kg FEMY-R7 for 7 days. In Campylobcter-like organism-detection test and bacterial identification, FEMY-R7 exerted a high bacteria-eliminating capacity at 30-100 mg/kg, comparably to 30 mg/kg pantoprazole. In contrast to a strong antacid activity of pantoprazole in a pylorus-ligation study, FEMY-R7 did not significantly affect gastric pH, free HCl, and total acidity, although it significantly decreased fluid volume at a low dose (10 mg/kg). The results indicate that FEMY-R7 eliminate H. pylori from gastric mucosa by directly killing the bacteria and preventing their adhesion and invasion, rather than by inhibiting gastric secretion or mucosal damage.

Analysis of Gene Mutations Associated with Antibiotic Resistance in Helicobacter pylori Strains Isolated from Korean Patients

BACKGROUND/AIMS: This study aims to identify the gene mutation pattern associated with antibiotic resistance for mainly used antibiotics in Helicobacter pylori strains isolated from Koreans. MATERIALS AND METHODS: Seventy-one H. pylori strains were isolated from gastric mucosal biopsy specimens. The specimens were cultivated and the resistance to 5 antibiotics were assessed by using agar gel dilution method. DNA sequencing was carried out to detect the resistance-related gene mutations. RESULTS: A point mutation at A2143G of 23S rRNA was observed in all of the clarithromycin resistant strains, but tetracycline resistant strains were not found. Substitution N562Y in penicillin binding protein 1 were observed in an amoxicillin resistant strain (minimum inhibitory concentration [MIC] 2.0microg/mL). Eleven (57.8%) out of 19 levofloxacin resistant strains showed amino acid substitution at N87K (8 strains), N87I, A88V and D91N in GyrA. The truncation in rdxA was detected in 8 (25.0%) out of 32 metronidazole resistant strains. Two out of the 7 patients who failed in first-line treatment of clarithromycin and amoxicillin showed A2143G mutation. CONCLUSIONS: 23S rRNA mutation is closely related to the failure of eradication, however, the fact that five people who have no gene mutation failed eradication implies that other factors are related. As MIC levels in clarithromycin and levofloxacin resistance strains are getting higher, their appropriate gene mutation is more correlated.

Analysis of Gene Mutations Associated with Antibiotic Resistance in Helicobacter pylori Strains Isolated from Korean Patients

BACKGROUND/AIMS: This study aims to identify the gene mutation pattern associated with antibiotic resistance for mainly used antibiotics in Helicobacter pylori strains isolated from Koreans. MATERIALS AND METHODS: Seventy-one H. pylori strains were isolated from gastric mucosal biopsy specimens. The specimens were cultivated and the resistance to 5 antibiotics were assessed by using agar gel dilution method. DNA sequencing was carried out to detect the resistance-related gene mutations. RESULTS: A point mutation at A2143G of 23S rRNA was observed in all of the clarithromycin resistant strains, but tetracycline resistant strains were not found. Substitution N562Y in penicillin binding protein 1 were observed in an amoxicillin resistant strain (minimum inhibitory concentration [MIC] 2.0microg/mL). Eleven (57.8%) out of 19 levofloxacin resistant strains showed amino acid substitution at N87K (8 strains), N87I, A88V and D91N in GyrA. The truncation in rdxA was detected in 8 (25.0%) out of 32 metronidazole resistant strains. Two out of the 7 patients who failed in first-line treatment of clarithromycin and amoxicillin showed A2143G mutation. CONCLUSIONS: 23S rRNA mutation is closely related to the failure of eradication, however, the fact that five people who have no gene mutation failed eradication implies that other factors are related. As MIC levels in clarithromycin and levofloxacin resistance strains are getting higher, their appropriate gene mutation is more correlated.

Antibiotic Resistance in Helicobacter pylori Strains and its Effect on H. pylori Eradication Rates in a Single Center in Korea

BACKGROUND: Clarithromycin, amoxicillin, metronidazole, tetracycline, and levofloxacin have been commonly used for the eradication of Helicobacter pylori. We compared the change in antibiotic resistance of H. pylori strains during two separate periods and investigated the effect of antibiotic resistance on H. pylori eradication. METHODS: H. pylori strains were isolated from 71 patients between 2009 and 2010 and from 94 patients between 2011 and 2012. The distribution of minimal inhibitory concentration (MIC) of 5 antibiotics was assessed using the agar dilution method, and H. pylori eradication based on the antimicrobial susceptibility of the isolates was investigated retrospectively. RESULTS: Antibiotic resistance rate against clarithromycin, amoxicillin, tetracycline, metronidazole, and levofloxacin for the 2009-2010 isolates were 7.0% (5/71), 2.8% (2/71), 0% (0/71), 45.1% (32/71), and 26.8% (19/71), respectively, and for the 2011-2012 isolates were 16.0% (15/94), 2.1% (2/94), 0% (0/94), 56.3% (53/94), and 22.3% (21/94), respectively. Multi-drug resistance for 2 or more antibiotics increased slightly from 16.9% (12/71) in the 2009-2010 isolates to 23.4% (22/94) in the 2011-2012 isolates. In follow-up testing of 66 patients, first-line treatment successfully eradicated H. pylori in 50 patients (75.8%) and failed in 4 of 7 patients (57.1%) in a clarithromycin-resistant and amoxicillin-susceptible group. CONCLUSIONS: We observed an increase in resistance to clarithromycin and an overall increase in multi-drug resistance during the 2 study periods. The effectiveness of the eradication regimen was low with combinations of clarithromycin and amoxicillin, particularly in the clarithromycin-resistant group. Thus, eradication of H. pylori depends upon periodic monitoring of antimicrobial susceptibility.

Apoptosis signal-regulating kinase 1 (ASK1) is linked to neural stem cell differentiation after ischemic brain injury

Neural stem cells (NSCs) have been suggested as a groundbreaking solution for stroke patients because they have the potential for self-renewal and differentiation into neurons. The differentiation of NSCs into neurons is integral for increasing the therapeutic efficiency of NSCs during inflammation. Apoptosis signal-regulating kinase 1 (ASK1) is preferentially activated by oxidative stress and inflammation, which is the fundamental pathology of brain damage in stroke. ASK1 may be involved in the early inflammation response after stroke and may be related to the differentiation of NSCs because of the relationship between ASK1 and the p38 mitogen-activated protein kinase pathway. Therefore, we investigated whether ASK1 is linked to the differentiation of NSCs under the context of inflammation. On the basis of the results of a microarray analysis, we performed the following experiments: western blot analysis to confirm ASK1, DCX, MAP2, phospho-p38 expression; fluorescence-activated cell sorting assay to estimate cell death; and immunocytochemistry to visualize and confirm the differentiation of cells in brain tissue. Neurosphere size and cell survival were highly maintained in ASK1-suppressed, lipopolysaccharide (LPS)-treated brains compared with only LPS-treated brains. The number of positive cells for MAP2, a neuronal marker, was lower in the ASK1-suppressed group than in the control group. According to our microarray data, phospho-p38 expression was inversely linked to ASK1 suppression, and our immunohistochemistry data showed that slight upregulation of ASK1 by LPS promoted the differentiation of endogenous, neuronal stem cells into neurons, but highly increased ASK1 levels after cerebral ischemic damage led to high levels of cell death. We conclude that ASK1 is regulated in response to the early inflammation phase and regulates the differentiation of NSCs after inflammatory-inducing events, such as ischemic stroke.

Prolonged survival of islet allografts in mice treated with rosmarinic acid and anti-CD154 antibody

Pancreatic islet transplantation can correct the abnormal glucose metabolism of Type 1 diabetes. Although immunosuppressants greatly reduce the acute rejection rate in transplant patients, the long-term side effects can be debilitating. Therefore, researchers are seeking to develop new immunosuppressive regimens that induce maximal levels of immunosuppression with minor side effects. Rosmarinic acid (Ros A) is a secondary metabolite of certain herbs and has multiple biological activities, including anti-inflammatory effects. Here, we have investigated whether treatment of mice with a combination of Ros A and anti-CD154 monoclonal antibody (MR1) improves islet allograft survival in a murine model. After transplantation, the mice were treated with either Ros A, MR1, or both (the "double" treatment). Allograft survival was prolonged in the double-treated animals compared to animals that received only Ros A or MR1. As is the case with the single-treated animals at 15 days after transplantation, the double-treated recipients did not display a significant decrease in the expression of cytokines or the population of activated T cells. Infiltrating CD3+ T cells were reduced in the MR1- or double therapy relative to control or RosA group. However, at the same time point, double-treated graft showed fewer apoptotic cells and increased expression of insulin and glucagons, compared to the single-treatment groups. Furthermore, long-term (>150 days) allografts that were received with double therapy exhibited larger islet clusters and contained more insulin- and glucagon-positive cells, relative to the MR1-treated grafts. In conclusion, treatment with both Ros A and MR1 has a synergistic effect in murine islet allotransplantation.